The present invention relates to a grout bag, sometimes referred to as an inflatable bag, for use in mine support and also to a method of installing the support.
Such grout bags are used to support the hanging wall or roof in underground mining operations relative to the footwall or floor. The grout bags generally are filled with a liquid settable grout which sets solid using cementitious or other suitable binding material.
Props have been used for supporting the mine roof for many years. More recently inflatable grout bags have been employed as mine props whereby they are positioned in a deflated condition with the upper end thereof secured to the mine roof. The bag is then inflated to a substantial pressure with a settable grout and thereafter permitted to cure.
Such grout bags are also referred to as pillar bags and they are generally supported and reinforced over their vertical length by metal hoops or other reinforcing structure against expansion in the traverse direction when filled with a liquid settable material.
Problems incurred with existing grout bags are that they are generally expensive because of the associated elaborate reinforcing structures employed and further because considerable labor is involved in their erection. Additionally, reinforced grout bags of the prior art have insufficient load carrying capacity. Such prior art grout bags usually have a residual load capacity of approximately 250 kips to 300 kips, 125 tons to 150 tons, with about 9″ of displacement. It is a principal object of the present invention to provide a pumpable crib bag having a residual load capacity which is exceptionally greater.